1. Field of the Invention
This invention relates generally to tape cassette cases and, specifically, relates to a tape cassette latch mechanism that prevents the case from inadvertent openings.
2. Description of the Prior Art
Tape cassette cases for storing cassettes so as to protect the cassettes from dust and humidity are known, for example, from UK Patent Specification No. 2 022 555A and having a common assignee herewith, the case described therein being illustrated in FIG. 1 of the accompanying drawings. In FIG. 1, a cassette case comprises main wall 1 and cover wall 2, hingedly connected by end wall 3. Secured to main wall 1 is an identical pair of reel lock members 4 and 5 that engage the reels of the cassette, when it is placed into the case, so that unwinding of the cassette reels does not occur. The case, which is made from a resilient material, is provided with a pair of releasable locking arrangements comprising a pair of rectangular assemblies 6 mounted on peripheral wall 7 extending from cover wall 2, and a pair of corresponding recesses 8 formed in peripheral wall 9 extending from main wall 1. Each of the rectangular assemblies 6 has a respective protrusion 6a and 6b formed thereon, and each of the recesses 8 has a respective aperture 8a and 8b corresponding to protrusions 6a and 6b, respectively. Apertures 8a and 8b are arranged to receive protrusions 6a and 6b, so that, when the case is in the process of being closed, protrusions 6a and 6b slide over recesses 8 in peripheral wall 9 and become inserted into apertures 8a and 8b, thereby locking the case. The case may be unlocked by exerting an opposing separating force on main wall 1 and cover wall 2 to urge protrusions 6a and 6b out of apertures 8a and 8b.
Peripheral walls 7 and 9 extend from main wall 1 and cover wall 2, respectively, so that, when the case is closed, peripheral wall 7 slides over the outwardly facing surface peripheral wall 9, so as to provide a seal to prevent dust and other particles from entering the closed case and being deposited on the tape housed in the cassette that has been placed in the case.
The above-described tape cassette case and other prior art cases have the disadvantage that the locking arrangement for keeping the case closed is not sufficiently secure to prevent the case from opening by accident, thereby, putting the safety of the cassette at risk. Furthermore, the locking arrangement of the above-described case is only operable if peripheral walls 7 and 9 of the case are made from a material sufficiently flexible and resilient to permit the members of the above-mentioned locking arrangement to be flexibly repositioned with respect to each other, thus imposing a constraint on the strength of the case, as well as a constraint on the security of the locking arrangement itself. Due to the required inherent flexibility of peripheral walls 7 and 9, and the fact that they overlap when the case is closed, small gaps exist in what is intended to be a seal formed between them, the gaps being sufficiently large for dust and humidity to enter the closed case.
Furthermore, such prior art cassette cases are not provided with facilities that enable them to be stacked one on the others conveniently and securely, therefore, problems exist in the safe transportation of a number of such cases, while ensuring that cassettes stored within them are protected.